refactor(open-sse): B1 consolidate media endpoint URLs into registry

- image/embed/tts/search base URLs derive from media.*Config.baseUrl /
  searchViaChat.endpoint (single source); handlers read PROVIDER_MEDIA.
- ~18 hardcoded endpoints moved: bfl/fal/stability/runway/hf/gemini/
  cloudflare/recraft/sdwebui/comfyui/nanobanana image, voyage embed,
  gemini/openrouter tts, chatSearch endpoints.
- Byte-identical: PROVIDERS 62 + alias 90 baselines, image buildUrl outputs.

Co-authored-by: Cursor <cursoragent@cursor.com>

open-sse/handlers/imageProviders/sdwebui.js

@@ -1,9 +1,12 @@
 // SD WebUI (AUTOMATIC1111) — local, noAuth
 import { nowSec } from "./_base.js";
+import { PROVIDER_MEDIA } from "../../providers/index.js";
+
+const BASE_URL = PROVIDER_MEDIA["sdwebui"]?.imageConfig?.baseUrl;
 
 export default {
   noAuth: true,
-  buildUrl: () => "http://localhost:7860/sdapi/v1/txt2img",
+  buildUrl: () => BASE_URL,
   buildHeaders: () => ({ "Content-Type": "application/json" }),
   buildBody: (_model, body) => {
     const { prompt, n = 1, size = "1024x1024" } = body;